1. Field of the Invention
The present invention relates to a method for joining, mixing-in or fading-in two signal segments which occur in the form of digital code word sequences, in particular of digitally coded audio signals free of interfering signals, with the use of signal scanning devices, i.e. reading devices, which are employed for determining an edit or fade-in location.
2. Description of the Prior Art
With audio signals which are stored digitally on a magnetic tape in accordance with the standards of the Audio Engineering Society, a problem exists in that the joining of two program segments cannot be easily accomplished free of interfering signals as in the same manner as has been customary with analog techniques. A difficulty arises in that the data blocks of the two program segments which are stored on separate tapes along with associated time codes, and error correction and parity bits, cannot be coupled with one another randomly, but only synchronously corresponding to a predetermined data block format. Also, a difficulty arises in editing digitally coded audio signals carried in magnetic tape in that the connection of two abruptly interrupted acoustic signal sequences is acoustically inadequate or impossible at every random location.
According to the prior art of audio signal recording, an "edit" which is free of interfering signals can be carried out if the edit location is followed by at least a several millisecond program pause. In order to determine a suitable edit location at the end of one program segment and at the beginning of another program segment to be coupled thereto, instantaneous values of the same level are sought in both program segments with the help of a display unit. Thereafter, the signal segments are connected with one another. The acoustic engineering processing of digitally-recorded programs, therefore, is made much more difficult than the processing of analog-recorded programs because of the lack of the customary "scissor diagonal cut" (a matching of analog signals) with the fade-in of two program segments so that the fade-in is free of interfering signals. This is also true because of the limitation of a skip-free location (matched signal levels) or program-free location (audio pause) and also because of the complicated determination of the optimum editing point through the use of a special display unit.